Conveying devices in the sense of the invention, which can also be termed transport devices, are escalators and moving walkways with a plurality of tread units or moving walkway plates, which are connected to form an endless conveyor. Users of the conveying devices stand on tread surfaces of the tread units or walk on the tread units in the same direction of movement as the conveying devices move or progress.
In the case of escalators, the tread units form escalator steps, hereinafter termed steps, and in the case of moving walkways the tread units form moving walkway plates, hereinafter termed plates. Escalators bridge, with a relatively large angle of inclination, greater distances in height such as entire storeys. Thereagainst, moving walkways run horizontally or at a slight inclination, but in general with smaller angles of inclination than escalators.
Typically, such conveying devices comprise drive runs constructed as step chains or plate chains. For the sake of simplicity merely drive runs are referred to in the following. These drive runs are driven in order to move the steps or plates in a transport direction and, in accordance with the state of the art, they are provided at uniform spacings with so-termed guide rollers. These guide rollers move or roll along dedicated or provided guide rails. In the region of the ends of the conveying devices the drive trains run, by the guide rollers, around deflecting wheels (for example chain wheels) and thus execute a change in direction. Slide elements can also be used instead of guide rollers or drag rollers. The slide elements or the rollable elements (guide rollers or chain rollers) are directly fastened to a step chain or plate chain serving as drive run, as described further above.
In addition to the step chains or plate chains inclusive of the slide elements or rollable elements fastened thereto two further rollers, which are termed drag rollers and roll or move along separate guide rails, are required for each step or plate.
The steps or plates have in the past been relatively complicated to produce or cast and are also expensive, since they have to be intrinsically very stable and torsionally stiff. Moreover, the steps or plates have to be made with a high degree of accuracy in order to guarantee quiet, jerk-free running. An essential element of the steps or plates is the lateral cheeks or step cheeks which have a significant supporting function. Hitherto, step cheeks or cheeks were typically made of aluminium, which did indeed lead to a low weight, but was accompanied by high costs, since the casting moulds or die-casting moulds were very expensive. Alternatively, use was made of step cheeks or cheeks screwed together from several different sheet metal parts and different cast or moulded parts. These step cheeks or cheeks were usually approximately twice as heavy as an aluminium (step) cheek.
JP 2004/292106 A describes a step, which has side cheeks, for a conveying device. These cheeks have a three-dimensional shape with a partly encircling flange. The features of a pair of lateral step cheeks substantially perpendicular to a tread element can thus be inferred from this specification. By contrast to FIG. 1, in FIGS. 7 and 12 of this specification there can be seen in the side cheeks a circle which can be interpreted as a cheek eye. However, this circle is not designated, and not clarified in the description. The position of the circle in any case excludes the possibility of a chain pin axle being mounted there.
JP 01308388 A or GB 2216825 A equivalent thereto shows in FIG. 1 a step with side cheeks which have a two-dimensional form and are constructed without an encircling edge. These side cheeks, which are formed from thick material, mount chain pin axles and drag roller axles in a usual manner. Side cheeks can be seen in FIG. 18, which are formed from thin sheet metal with a partly encircling edge. However, these side cheeks do not have eyes which could serve for the mounting of chain pin axles or drag roller axles. These axles are obviously mounted on more stable components which have to be connected with these cheeks.
DD 69443 relates to a step for escalators in which side cheeks are integrally connected with a front part. The front part is then covered by a riser element. A tread element covering the step has an angled portion which closes off the step at the side opposite the riser element. In that case the front part and the cheeks are of a flat construction, in which also no eyes for reception of angles are provided. Here, too, presumably the axles are mounted in more stable components which have to be connected with the cheeks.
The wish exists, particularly for more economic initial equipping of conveying devices, to replace the steps and plates by more advantageous components without in that case, however, impairing running smoothness, travel characteristics, stability, robustness and reliability as well as durability. Moreover, the production process should be simplified and accelerated.